It's been more than two months since every state and local hurdle was cleared to build a $2 billion extension of the Metro Transit Green Line, otherwise known as Southwest light rail. Since then, the Metropolitan Council officials who are driving this train have been watching for the federal signal that would allow the start of construction.

It has not come. The Met Council pleaded for Federal Transit Administration (FTA) action before Sept. 30, when two key civil contractor bids were set to expire and while sufficient time remained in the current construction season for preliminary work to begin. Those pleas went unheeded, with no explanation.

This week, Met Council officials asked bidders for a 45-day extension. Only the low bidder, Lunda/C.S. McCrossan at $799 million, agreed. That leaves Ames/Kraemer, which had bid $812 million, out of contention.

Will a 45-day extension be sufficient? "We're hopeful, but we're not sure," said Council Chair Alene Tchourumoff. "We've been given assurance that the FTA is actively reviewing" the Southwest application. A longer delay would almost certainly mean higher costs and could unravel the project's painstakingly woven funding arrangements, achieved through years of arduous political exertion by jurisdictions along the proposed 14.5-mile line.

If it's any solace to Tchourumoff, hers isn't the nation's only urban transit agency with a project waiting for a green light from the Trump administration's FTA. According to the advocacy group Transportation for America, about a dozen U.S. cities are in the queue for their share of $2.3 billion appropriated by Congress in the 2017 and 2018 fiscal years for new transit lines. Only $533 million, or 23 percent, of that money has been distributed.

Advocates are convinced that the FTA is doing an intentional slow-walk, knowing that delay can be fatal to new transit lines, Beth Osborne of Transportation for America told an editorial writer. President Donald Trump asked Congress last year to end federal funding for new transit projects. Instead — and despite the GOP-allied fossil fuel industry's hostility to public transportation — Congress in March reaffirmed its long-standing commitment to pay nearly half the cost of new urban lines. Congress' action reflects decades of bipartisan belief that the whole country benefits when goods and people move efficiently through the nation's largest metro areas.

A strong majority of Minnesotans have a similarly positive opinion about transit, according to a new survey commissioned by the Minneapolis Regional Chamber of Commerce. It found that 74 percent of the state's voters — including more than half of Republicans — support additional public investment in buses, trains and light rail.

Those results suggest growing awareness of the transportation demand that this region's projected growth will bring. Met Council planners say that by 2035, the number of people employed in downtown Minneapolis will climb 18 percent and the population that lives within a half-mile of Southwest light rail's 16 proposed stations will be up 56 percent. Accommodating the needs of the 2030s requires ample lead time. Already, the Southwest line is not expected to start service until 2023.

The Met Council isn't asking the FTA to start the flow of federal dollars in the next 45 days. All it seeks this year is a promise that if it starts spending its own funds — up to a requested $187.3 million — the FTA will provide reimbursement under a larger grant due to be awarded next year. That assurance should come without further delay — and Minnesotans in a position to exert influence with the federal agency, starting with Third District Republican U.S. Rep. Erik Paulsen, ought to apply it posthaste.